March 2010 Douro Insider

Flooding below Malvedos, late March 2010

After the storm right at the end of February there was the usual delay of a couple of days until the bulk of the rain percolated into the Douro.  The river then began to rise considerably, causing minor flooding at the bottom of some of the quintas but nothing too serious.  Perhaps the worst of the damage was on the road linking Pinhão to Régua where there were two separate rock-falls, one just upriver and another just downriver of the dam.  The resulting debris led to the closure of the road and a stretch of it still had not reopened by the end of the month.  It is thought that part of the hillside is geologically unsound and prone to further landslides in the future, with no obvious solution immediately apparent.

In spite of this slightly inauspicious beginning, the month started with a generally optimistic feeling in the air because (although there was still plenty of cloud around) there were also some patches of blue sky sighted, occasional sunny periods and a noticeable warming of temperatures.  One was left with the definite impression that the storm at the end of February must surely have marked, if not the end of winter itself, then at the very least that the worst was over.  The fact that the evenings were now long enough to get home after work in daylight also brightened up spirits which had taken on quite a gloomy outlook after so long under the rain.  This feeling was further reinforced by the first flushes of flying insects.  They emerged to take advantage of some early wild flowers just coming into bloom.  Could winter finally be over?

Of course it turned out not to be, and the spring honeymoon was short-lived indeed.  There was yet more bad weather rolling in by the end of the first week.  The puddles in the vineyards have now been there for so long that there are frogs living in them.  As luck would have it the weather brightened up again in the Douro from the 9th and gave us vital breathing space for tackling the weeds on the terraces, something that cannot be done in the rain.  But although we had clear skies in the north there were still snowfalls on higher parts of the Alentejo, and also reports of huge amounts of snow in northeast Spain, particularly in the Barcelona region.  Many parts of Italy and Bulgaria were also affected by snowfalls.  We certainly felt the cold weather here too, and the starry night time skies were accompanied by a return of the frost in certain parts of the Douro.  This situation would of course be very dangerous if it continued beyond budburst since the young shoots are very easily damaged by the formation of ice on them.

The last two weeks of the month brought half a dozen or so perfectly blue spring days and some quite pleasant warmth, but in the end it turned out to be yet another false start with March finally wrapping up on another downward trajectory.  The last couple of days were cold and wet again with hail falling at some of the quintas and a considerable amount pounding down over the rooves of the lodges in Gaia.  Hail is at least as dangerous for the vines as frost (particularly after flowering) so we are very much hoping that this will be the last of it.

Specific details of March’s weather for Pinhão raise an important point of note: the 100 mm of rain that fell there is extremely significant.  It means that, for the first time since our records began in 1967, there have been six consecutive months of triple digit precipitation values.  And it is also therefore the sixth month on the trot with an above average total, given that in no month is the mean value more than 100 mm.  As the graph below shows, the cumulative total for the current year (now at 349 mm) is already more than 60 % ahead of the average cumulative total for this stage, which stands at 215 mm.

When we take the temperatures into consideration too, March turned out to be rather similar to February in that it was both considerably wetter than usual and considerably colder.  The monthly average temperature of just 10.8º C was really very cold.  In fact it was the coldest March for a quarter of a century, the last colder one being back in 1985.  This was in many respects a result of abnormally low night-time temperatures – Pinhão had 10 consecutive sub 5º nights in the middle of the month, for instance.  This was not entirely offset by some very reasonable daytime temperatures, with six days of the month climbing comfortably above 20º.  There was a noticeable disparity between the daily maximum and minimum temperatures that coincided with the spell of clear skies, and a contrasting contraction of the daily range on the wetter days.  Curiously Europe’s cold month was significantly out of line with the general situation for the rest of the planet.  Analysts from the National Oceanic and Atmospheric Administration in the US declared that the combined land and ocean average global temperature for March was the warmest on record, and blamed this on El Nino.

As we move from the weather to the vineyards, the first point of note is that March almost inevitably sets the viticultural year’s phenological calendar running.  The second point of note is that both February and March registered temperatures more than 1º below average, which sends a clear message to the vines that it isn’t time to wake up yet.  As a result budburst was delayed quite considerably, and the average date for the various main varieties (observed in an experimental vineyard just outside Pinhão) was the 25th March.  This does represent a significant delay, given that the corresponding date for the last two years was the 17th March.  Data provided by ADVID show that this year has had one of the lowest summations of active temperatures (daily averages above 10º) so far this century, so it is not surprising that the vineyards are late to get started.  The days since the beginning of January are clearly more important for these calculations than the ‘autumn’ period which, many will remember, was generally warmer than average.

What this meant in practice was that we should have had more time than usual for removing the winter weeds from the vineyards, had the terrible weather not kept us waiting until a small window of opportunity appeared in the middle of the month.  A few dry and sunny days were exactly what we had been waiting for, and our viticultural teams sprung into action.  It is particularly important that the manual clearing of the more stubborn plants from the banks between the terraces be carried out before budburst so as to avoid accidental damage to the delicate vine shoots.  Post-pruning trellis maintenance was also on the roster in places, although some might argue that the soil was still too wet to tighten the wires properly without pulling the end assemblies out of alignment.  Meanwhile the early spring duo of replanting falhas (missing vines) and regrafting continued at many quintas: both were widespread this month across the region.

By this stage, a number of properties were also involved in despedrega (stone clearing), an activity which is always useful in soils as stony as ours (but can be carried out at any convenient time).  This is an important practice for the sake of efficiency, to enable the smooth passage of both people and machinery through the vineyards.  Tractors on tracks are particularly vulnerable to stones since they have no suspension, and tend to ride up into the air over rocks before see-sawing down the other side when the point of equilibrium is crossed.  All of our equipment is designed to work parallel to the ground, and some in particular (prepruners, trimmers or mowers, for instance) can cause significant damage if this flat angle is not maintained.

Speaking of mowers, the general warming of daytime temperatures after such a wet winter meant that the cover crops (which are now virtually obligatory under new laws) suddenly started to grow very quickly, and even hinted at flowering.  In many places they were almost up to the height of the cordon wire, a situation which would not be desirable as it is sure to create a humid microclimate along the under-vine strip, and therefore also increase the danger posed by fungal diseases.  This development resulted in several vineyards having to start the first mid-row cut still in March, admittedly far earlier than usual or perhaps desirable.  The moisture in the topsoil already suggests that the mowers will get plenty of use this year, and the economic consequences of so much time spent cutting the grass will surely be felt.  There may also be difficulty in freeing up tractors for mowing the cover crops during the treatment season; a wet winter again threatens problems with fungal diseases in the spring.  The logistics involved in juggling all these simultaneous requirements can be something of a headache, especially when the usual (but nevertheless unpredictable) break-downs are factored in to the equation.

It goes without saying that the saga of the winter damage continues, and will probably not even be finished by the end of next month.  Track repairs were still being carried out across the region and many terraces remain to be rebuilt when the earth dries out enough to make this possible.  The Douro’s emblematic pre-phylloxera patamares, although spectacular, have taken an awful beating this winter with long stretches of wall collapsing as the waterlogged schist simply rots, crumbles and eventually gives way under the weight of water in the soil.  Rebuilding them, which is now also obligatory, was ongoing and will be for some time yet.  And, as has been said time and time again in recent reports, the other major effect of wet weather at this time of year is that the bulldozers preparing the terrain for new plantations lost several days of work where the ground was too waterlogged to work on.

The only other activity of note this month from all the various Douro properties went on not in the vineyards but in the olive groves – pruning the olive trees.  A brief description of the reasons for this undertaking and of the procedure itself was given at the end of last month’s report.  Like vines, olive trees only produce flowers (and therefore fruit) on shoots of the previous year’s growth.  Needless to say, therefore, that if new growth is not stimulated by regular (although not as frequently as annual) pruning, production decreases considerably and picking becomes more difficult.  As a result many farmers took advantage of this relatively calm period, and the fact that there was not much else that they could do, to tackle some olive tree trimming.  The ideal distribution of labour would probably be to prune about a third of the olivais each year, making it a three-year cycle.